Magnetically operated envelope enclosed high-voltage relay

ABSTRACT

A high-voltage vacuum relay is provided of the double-pole, double-throw type and which has particular application to medical purposes, although it is not limited to uses. The movable and fixed contacts of the relay are mounted with an envelope, with the movable contacts supported by the envelope for pivotal movement, and for selective engagement with the fixed contacts in a manner such that under no conditions will one contact of any pair open without the other.

United States Patent Inventor Victor E. De Lucia Los Angcles, Calil.

Appl. No. 15,762

. Filed Mar. 2, 1970 Patented Sept. 14, 1971 Assignee Torr Laboratories,Inc.

Los Angeles, Calif. Continuation-impart of application Ser. No. 840,380,July 9, 1969.

MAGNETICALLY OPERATED ENVELOPE ENCLOSED HIGH-VOLTAGE RELAY 7 Claims, 10Drawing Figs.

U.S. Cl 200/144, 335/153, 335/203 Int. Cl 1101b 33/66 Field of Search200/ 144.2,

[56] References Cited UNITED STATES PATENTS 1,879,349 9/1932 Lederer.200/166 H 2,834,847 5/1958 Jennings... 200/144 B X 2,912,539 11/1959Jennings 200/144BX 2,920,162 1/1960 Steward et al. 335/151 3,250,8865/1966 De Lucia 200/144 13 X 3,483,492 12/1969 Mirbeth 335/202 X PrimaryExaminer-Robert S. Macon Attorney-Jessup & Beecher ABSTRACT: Ahigh-voltage vacuum relay is provided of the double-pole, double-throwtype and which has particular application to medical purposes, althoughit is not limited to uses. The movable and fixed contacts of the relayare mounted withan envelope, with the movable contacts supported by theenvelope for pivotal movement, and for selective engagement with thefixed contacts in a manner such that under no conditions will onecontact of any pair open without the other.

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' sum 2 or 2 Afrakwajr MAGNETICALLY OPERATED ENVELOPE ENCLOSEDHIGH-VOLTAGE RELAY BACKGROUND OF THE INVENTION This application is acontinuation-in-part of copending application Ser. No. 840,380 which wasfiled July 9, I969, in the name of thepresent inventor;

The relay of this invention is of the same general type as the relaydescribed in US. Pat. No. 3,250,886, which issued May 10, 1966, andwhich is assigned to the present assignee. As pointed out in thepatent,in defribrillato'r systems, for example, a double-pole,doublethrow relayis used'selectively to introduce a high voltage to the heart of thepatient under precisely controlled conditions.

- The relay is required to operate at high voltages,'so that vacuumrelays are well suited for the purposes because their contacts areenclosed within an evacuated envelope, and contact deterioration-ismaterially reduced. However, ionization effects in the vacuum relays hassubstantially limited their usefulness in this area. The relay of thepresent invention incorporates an envelope filled with a pressurizeddielectric gas, such as sulfur hexafluoride (SP to reduce the ionizationwithin the envelope and also to provide a cooling effect.

, In order to obviate any possible hazard which could otherwise becaused due to the use of such gas, a rubberlike resilient enclosure isprovided in the relay of the invention formed, for example, of asuitable silicone rubber, which is molded to and surrounds the envelopeof the relay so as to eliminate the possibility of breakage of theenvelope. Such breakage should be prevented due to the fact that sulfurhexafluoricle has a tendency to break down into dangerous com ponents inthe event of envelope breakage with resulting explosion, the componentsincluding corrosive fluorides.

With the inclusion of the aforesaid protective enclosure, thehexafluoride pressure within the envelope can be increased up to, forexample, 10 atmospheres, so as to provide improved dielectric effects toprevent ionization, and also to improve cooling. The aforesaid enclosurenot only protects against accidental breakage of the envelope, but alsoseals any cracks which might occur.

. In the practice of the invention, it has also been found thatmixturesof sulfur hexafluoride with -30 argon, and 0-10 nitrous oxide,also provides an effective gaseous atmosphere within the relay toprevent the aforesaid ionization effects, and to provide desiredcooling. Also, activated alumina may be included into the housing as agetter for thecorrosive fluorine compounds, in order to prevent harmfuleffect should the sulfur hexafluoride tend to break down.

' In the heart defribrillator systems, for example, it is most importantthat both of the normally closed contacts of the relay open when therelay is energized and that both of the normally open contacts open whenthe relay is deenergized. In either instance, should one contact openwithout the other, deleterious effectson the patient could result. Theimproved relay of the present invention is particularly constructed tooperate over extended intervals of time at high voltages, and is ideallysuited for defribrillation uses, although not limited to such uses.

As described above, the inclusion of the pressurized sulfur hexafluoridewithin the relay envelope minimizes ionization within the relay,"and theprotective enclosure of the relay prevents any envelope breakage hazard,with resulting explosion and reduction of the pressurized sulfurhexafluoride into corrosive flourides and fluorines.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevation, partly insection, and with the protective casing shown in shadow form, of animproved relay FIG. 4 is a side elevation of the relay and showingparticularly the configuration of the outer protective casing;

FIG. 5 is a bottom view of the relay taken along the line 5- 5 of FIG.4;

FIG. 6 is a top view taken along the line 6 .-6 of FIG, 4;

FIG. 7 is a side view of the movable contact assembly used in the relayof FIG. I; I

FIG. 8A is a bottom view of the movable contact assembly taken along thelines 8A8A of FIG. 7'; I t

FIG. 8B is a top plan view of the movable contact assembly taken alongthe line 8B8B of FIG. 7; and

FIG. 9 is a typical discharge circuit in which the relay of the presentinvention may be included.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT The relay illustratedin the drawing includes, for example, and envelope 10 which may beformed of glass or other suitable vitreous material. The envelope 10 mayhave a generally cylindrical configuration with a closed top and an openhottom, A metal ring 12, formed of appropriate material such as Kovar,is sealed to the periphery of the open end of the en.- velope l0, andthe ring 12 includes an integral lower radially extending flangeportion. I

An armature assembly, designated generally as 14, is mounted to the ring12, and the armature assembly extends into the envelope 10, as shown inFIG. 1. The envelope lllis.

filled with a suitable inert gas, as will be described. The top of theenvelope 10 has a bulblike configuration for added strength to withstandthe internal pressure of the inert gas. The armature assembly includes,for example, acylindricalshaped member 15 formed of appropriate magneticmaterial and including a peripheral radially extending flange 15a. Thehousing I5 is mounted to the ring 12, as shown in FIG. 1, by welding theflange 15a to the flange of the ring I2, or by otherwise affixing thetwo flanges to one another. The lower portion of the magneticcylindrical member 15 is threaded, as shown in FIG 3, for example, formounting purposes.

A central core member 16 formed of appropriate magnetic material ismounted concentrically within the cylindricalshaped magnetic housing 15,and is held in place, for example, by means of a washer I7 ofnonmagnetic material and which is welded to the housing 15 and to thecentral core 16. The energizing coil for the relay is supported withinthe cylindrical housing 15 and extends around the central core I6. 7

A tube 18 is threaded into the lower end of the core lfijandcommunicates with a passageway 20 which extends through the core 16 andinto the interior of the envelope 10. The sulfur hexafluoride, or itsequivalent, may be introdll fid into the in-v terior of the envelopeit), through the tube 18 until a desired pressure is reached. The tube18 is then pinched off and sealed, as shown in FIG. I. The remainingpart of the tube 18 may be securely held in the core 16 by means, forexample, of a nut 22, also shown in FIG. 1 which also serves to retainthe energizing coil within the cylindrical member 15- Appropriateterminals 24 are provided for the energizing coil within the cylindricalmember, so that the coil may be appropriately energized.

Other insert gases such as argon or nitrous oxide may be used in placeof the sulfur hexafluoride, or as a mixture therewith. A satisfactorymixture of gases has beenused cornprising percent sulfur hexafluoride,10 percent argon and 5 percent nitrous oxide. As mentioned above, theinert gas, or gases, are introduced into the interior of the envelopethrough the passageway 20 extending through the central pole of themagnetic core 16, and which includes an internally threaded lower endportion for receiving the threaded tube 13. the tube 18 and the centralpart of the core 16 serving additionally not only as a passageway forthe gas introduced into the envelope, but also as a support for the nut22 which retains the nfil'g izing coil within the cylindrical housing15.

Helium may be introduced into the interior of the envelope together withthe other gases referred to above as a coolant,

The high pressure gas within the envelope prevents ionization in thatthere is no current flow through the relay until actual contact is made.This use of a dielectric gas within the envelope is important when therelay is used for medical purposes, since it prevents preionizationwithin the envelope and a precontact jolt of electrical current to thepatient.

The armature assembly 14 includes a magnetic armature 26 which is hingedto a member 28, and which extends across the upper end of the core 16,and across the annular space between the core and the upper edge of themagnetic housing 15. The member 28 is affixed to the upper end of thehousing 15, for example, by spot welding or other suitable means. Aspring 27 (FIG. 3) is mounted in a recess formed in the upper end of thehousing 15, in a position to surround the upper end of the core 16. Thespring 27 bears against the armature 26, and biases it in a clockwisedirection in FIGS. 1 and 2. The armature assembly 14 includes a pair ofupright support arms 29 which are welded, or otherwise affixed to thearmature 26, and which extend upwardly within the envelope 10, as shownin FIGS. 1, 2 and 3.

The support arms 29 each have a slot 31 in its upper end, as shown inFIGS. 1 and 3. When the relay is deenergized, the spring 27 causes thearmature 26 to be biased in a counterclockwise direction, as mentionedabove, so that the support arms 29 normally have a tilted inclination,as shown in FIG. I, and as shown by the dotted line in FIG. 3. Then,when the relay is energized, the armature 26 is pulled down against thebias of the spring 27, so that the support arms 29 assume the uprightposition shown by the solid line in FIG. 3.

The relay assembly includes four terminal pins, which are designated 30in FIGS. 1 and 2, and which, as best shown in FIG. 2, extend through theenvelope in a radial direction. The terminal pins 30 also serve as fixedcontacts for the relay, as will be described. A further pair of terminalpins, designated 38 in FIGS. 1 and 2, extends through the wall of theenvelope 10, between the pins 30, as shown clearly in FIG. 2. Theterminal pins, designated 38 in FIGS. 1 and 2, extends through the wallof the envelope 10, between the pins 30, as shown clearly in FIG. 2. Theterminal pins 38, for example, constitute the movable contact terminalsfor the relay in the double-pole, double-throw embodiment disclosedherein. In one position of the relay, for example, the pins 38 arerespectively connected to the pins 30 to the left of FIG. 2, and in thesecond position of the relay, the pins 38 are connected respectively tothe pins 30 at the right of FIG. 2.

The selective connection between the pins 38 and the pins 30 is achievedby means of a pair of arcuate movable contacts 34, which are pivotallysupported on the respective pins 38, and which are interconnected bymeans of a rod 32 composed of sapphire or other appropriate insulatingmaterial. As shown in FIG. I, the rod 32 is displaced down form thecommon axis of the pin 38, and it extends into the slot 31 at the top ofthe support arms 29. The rod 32 is mechanically coupled to therespective arcuate contacts 34 by means of respective U- shaped clips 33which are mounted to the arcuate contacts 34 by means, for example, ofbent over ears 33a. A pair of resilient strips 35 may be mounted in theslot 31 to bear against the rod 32 to provide coaction between the rodand the support arms 29.

The use of the two-spaced support arms 29 extending between the armatureand the sapphire rod 32 has been found to be more advantageous than asingle support arm in that there is less tendency for the two supportarms to fracture the .rod 32 than is the case of a single support arm.In a constructed embodiment, the two support arms were spaced fiveeightsinch apart, and were found to have the added advantage in that thereis'not tendency with the two support arms for the movable contactassemblies to twist in the event that a contact should become welded,and positive action of the assembly is assured. When the relay is usedfor medical purposes, it is im- .portant that every precaution be takenso that the contacts open and close only as a pair, and notindividually.

A pair of washers 40 (FIG. 2) formed, for example, of molybdenum orother appropriate material are mounted on each of the terminal pins 38between the corresponding movable contact assemblies and the inner wallof the envelope [0 and on the opposite sides thereof, the washers 40being in contact with the respective U-shaped clips 33. These washersserve to carry the current from the pins 38 to the movable contactassemblies and thereby prevent erosion around the holes in the clips 33which receive the pins 38 as the electric current flows from the pins tothe movable contacts. The outer washers 40 also serve to prevent themovable contact assemblies from riding against the inner surface of theenvelope 10. Further to prevent such erosion, conductive tabs, such asthe tabs 39 in FIGS. 7 and 8A may be welded on the underside of eachmovable contact assembly and resiliently biased against thecorresponding terminal pin 38.

As shown in FIGS. 7, 8A and 8B, for example, the arcuate contactassemblies 34 each include a rigid arcuate body portion 340 which iscomposed, for example, of steel or Kovar, or other appropriate material,with a conductive plating of, for example, copper, on its lower face inFIG. 7. Each contact assembly 34 also includes an arcuate resilient leafportion designated 34c, and which may be integral with the clip 33. Theresilient leaf portion 340 also has an arcuate shape, matching themember 34a. The leaflike resilient member 34c may be formed, forexample, of molybdenum, and is bowed.

out from the solid rigid member 34a, as best shown in FIG. 7. The clip33, for example, may be formed of an appropriate material such asnickel. The ears 33a are used to attach the clips 33 and leaf portions340 to the rigid portions 34a. This obviates any need to weld theportions together, which is difficult with refractory materials, such asmolybdenum, and which tends to crystalize and deteriorate the materials.

Tungsten contact buttons 41 are mounted on the ends of the leaf portions34a. The purpose of the buttons 41 is to make the contact area small sothat a higher current flows between the movable contacts and the fixedcontacts for higher temperature. The high temperatures serves to breakdown the insulating film of the electrolyte gas which tends to form overthe contact areas.

The bowed resilient leaf section 340 is the first part of the movablecontact assembly 34 to engage a pin 30 when the relay is moved to oneposition and is the last part of the movable contact assembly 34 toleave the corresponding terminal pin 30 when the relay is moved to theother position. The assembly is such that contact bounce is prevented,and the relay may be operated at an extremely high rate of speed, withclean pulses being produced each time the contacts make, and with aminimum contact erosion.

As shown in FIG. 1, for example, the threaded portion of the housing 15may extend down into a metallic collar designated 70, and which mayinclude an apertured flange 70a, for mounting purposes. The terminals 24for the energizing coil of the relay may be connected to appropriateterminal connections 66 extending radially through the mounting collar70, and insulated therefrom. The connections from the terminals 24 tothe terminals 26 may be achieved, for example, by wires 65 shown in FIG.5.

The tubular envelope 10 is preferably surrounded by a resilient casing60, which is molded directly to the envelope and to the upper end of thecollar 70. The casing 60 is formed, for example, of an appropriaterubberlike substance, and silicone is appropriate for the purpose. Themolded rubberized casing 60 serves as a protection for the relay unit,and it precludes any possibility of breakage of the envelope 10, withthe resulting explosion and escape .of the pressurized gas within theenvelope. The terminal pins 30 and 38 are equipped with aperturedconnector tabs 30a, 38a and wires 62 and 64 are soldered to the tabs andprotrude through the upper end of the casing 60, as shown in FIGS. 4 and6.

As mentioned above, the relay of the invention has utility in themedical field, and particularly for heart defribrillation purposes.However, it is to be understood, of course, that such a use is referredto herein for illustrative purposes only, since the relay does havegeneral utility.

A typical discharge circuit for the relay, when used for heartdefribrillation purposes, is shown in FIG. 9. For example, the normallyopen fixed contacts 62 of the relay may be connected to the patient, whois designated 100. The common contacts 64 may be connected to a seriescombination of a coil 102 and capacitor 104. The coil 102, for example,may have an inductance of 42 millihenries, and the capacitor may have acapacity of 35 microfarads. The normally closed contacts 62 areconnected across a 5 kilovolt direct current source designated 106.

When the relay is in the deenergized condition shown in HO. 9, thecapacitor 104 is charged to a peak value. Then, when the relay isenergized, the charge on the capacitor is passed through the patient.

AConstructed double-pole, double-throw embodiment of the relay, such asdescribed above, exhibits the following characteristics:

, 25 volts direct current volts direct current milliseconds 500microseconds.

Maximum Pull-in Voltage Maximum DropOut Voltage Maximum Pull-In Time at50 volts DC Maximum Contact Bounce The aforesaid parameters, of course,are provided merely by way of example, and are not intended to limit theinvention in any way.

What is claimed is:

l. A relay including: an envelope having a generally tubularconfiguration; a first electrically conductive contact pin extendingradially into said envelope; a first arcuately shaped movable contactextending transversely to the axis of said first contact pin;electrically conductive means affixed to an intermediate part of saidmovable contact and pivotally mounted on said first contact pin to causesaid movable contact to be electrically connected to said first contactpin; a pair of further electrically conductive pins extending radiallyinto said envelope on each side of said first pin to be engagedselectively by the ends of said movable contact as it is moved pivotallybetween a first and a-second angular position; and magnetic armaturemeans mounted in said envelope and mechanically coupled to said movablecontact to rotate said movable contact selectively about the axis ofsaid first contact pin between said first and second angular positions.

2. The combination defined in claim 1, in which said envelope is filledwith a high pressure gas to prevent ionization between said contacts andto provide cooling therefor, a protective casing completely enclosingsaid envelope and formed of a resilient plastic material, and whichincludes electric wires connected to said electrically conductive pinsand protruding through said protective casing.

3. The relay defined in claim 1, and which includes a secondelectrically conductive contact pin extending radially into saidenvelope diametrically opposite said first pin and coaxially therewith;a second arcuate movable contact pivotally mounted on said secondcontact pin at an intermediate part of said arcuate movable contact; asecond pair of further electrically conductive contact pins extendingradially into said envelope on each side of said second pin to beengaged selectively by said second movable contact as it is rotatedbetween a first and a second angular position about the the common axisof said first and second contact pins; and insulating rodinterconnecting said first and second movable contacts parallel to saidcommon axis but displaced therefrom, said magnetic armature means beingmechanically coupled to said last-named rod.

4. The combination defined in claim 1, and which includes a washermounted on said first contact pin between the inner wall of saidenvelope and said first movable contact to prevent said first movablecontact from moving against said wall and to act as a current shuntbetween said first contact pin and said first movable contact.

5. The relay defined in claim 1, in which said first movable contactincludes an arcuate rigid portion, and an arcuate resilient leaf portionadjacent said rigid portion and being bowed outwardly therefrom so as toprovide a resilient engagement with said further electrical contact pinsas said movable contact is moved between its first and second angularpositions to minimize contact chatter and bounce as said movable contactengages said further contact pin, said leaf portion being composed ofrefractory electrically conductive material and being mounted on saidrigid portion by bent over ears, and a pair of contact buttons mountedon said resilient leaf portion at the ends thereof selectively to engagesaid further contact pins.

6. The relay defined in claim 3, and which includes a pair of supportarms mounted in spaced relationship on said magnetic armature means andextending to spaced positions along said insulating rod to mechanicallycouple said magnetic armature means to said insulating rod.

7. The relay defined in claim 1, and which includes a resilient lugaffixed to said movable contact and resiliently engaging said firstcontact pin to serve as an electric path between said first contact pinand said movable contact.

1. A relay including: an envelope having a generally tubularconfiguration; a first electrically conductive contact pin extendingradially into said envelope; a first arcuately shaped movable contactextending transversely to the axis of said first contact pin;electrically conductive meaNs affixed to an intermediate part of saidmovable contact and pivotally mounted on said first contact pin to causesaid movable contact to be electrically connected to said first contactpin; a pair of further electrically conductive pins extending radiallyinto said envelope on each side of said first pin to be engagedselectively by the ends of said movable contact as it is moved pivotallybetween a first and a second angular position; and magnetic armaturemeans mounted in said envelope and mechanically coupled to said movablecontact to rotate said movable contact selectively about the axis ofsaid first contact pin between said first and second angular positions.2. The combination defined in claim 1, in which said envelope is filledwith a high pressure gas to prevent ionization between said contacts andto provide cooling therefor, a protective casing completely enclosingsaid envelope and formed of a resilient plastic material, and whichincludes electric wires connected to said electrically conductive pinsand protruding through said protective casing.
 3. The relay defined inclaim 1, and which includes a second electrically conductive contact pinextending radially into said envelope diametrically opposite said firstpin and coaxially therewith; a second arcuate movable contact pivotallymounted on said second contact pin at an intermediate part of saidarcuate movable contact; a second pair of further electricallyconductive contact pins extending radially into said envelope on eachside of said second pin to be engaged selectively by said second movablecontact as it is rotated between a first and a second angular positionabout the the common axis of said first and second contact pins; andinsulating rod interconnecting said first and second movable contactsparallel to said common axis but displaced therefrom, said magneticarmature means being mechanically coupled to said last-named rod.
 4. Thecombination defined in claim 1, and which includes a washer mounted onsaid first contact pin between the inner wall of said envelope and saidfirst movable contact to prevent said first movable contact from movingagainst said wall and to act as a current shunt between said firstcontact pin and said first movable contact.
 5. The relay defined inclaim 1, in which said first movable contact includes an arcuate rigidportion, and an arcuate resilient leaf portion adjacent said rigidportion and being bowed outwardly therefrom so as to provide a resilientengagement with said further electrical contact pins as said movablecontact is moved between its first and second angular positions tominimize contact chatter and bounce as said movable contact engages saidfurther contact pin, said leaf portion being composed of refractoryelectrically conductive material and being mounted on said rigid portionby bent over ears, and a pair of contact buttons mounted on saidresilient leaf portion at the ends thereof selectively to engage saidfurther contact pins.
 6. The relay defined in claim 3, and whichincludes a pair of support arms mounted in spaced relationship on saidmagnetic armature means and extending to spaced positions along saidinsulating rod to mechanically couple said magnetic armature means tosaid insulating rod.
 7. The relay defined in claim 1, and which includesa resilient lug affixed to said movable contact and resiliently engagingsaid first contact pin to serve as an electric path between said firstcontact pin and said movable contact.